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code review checklist

Code Review Checklist – What to Include?

Estimated read time: 11 minutes
Faiza Khalid

Faiza Khalid

CIS engineerDeveloperTech Writer

Are you interested in a code review checklist for your software code?

Strict code reviews help developers spend more time delivering new features and less time fixing bugs. 55% of the teams following proper code review guidelines state they are highly satisfied with their work process. 64% of survey participants use code reviews as a technical tool to train new developers.

Conducting a code review requires a deep understanding of software defect prevention, a range of development technologies, several code security techniques, cutting-edge secure technologies like blockchain, best coding practices, etc.

If you don’t have a professional team with this relevant expertise to take on the task, then submit a request for a complimentary discovery call, and one of our tech account managers who managed similar projects will contact you shortly.

While the benefits of code reviews are very clear for development teams, the question is how to conduct a thorough code review that helps to remove bugs, ensure meeting all functional and non-functional requirements, etc., while improving cohesion between developers and testers. 

Let’s find out by discussing a code review checklist in detail.

A Code Review Checklist

Your code review checklist should cover the following aspects:

1. Feature Requirements

Your code review process starts with a fundamental question. “Does the software code meets all the feature requirements decided in the planning phase?” If the answer to this question is no, then you should postpone your code review until your software offers the full functionality as expected by the end-users.

Some of the essential questions you need to consider while reviewing the features and functionality of a code include the following:

  • Does the code work as expected?
  • Does the new feature a sign of feature creep?
  • Are there any bugs or errors in feature implementation?
  • Do all code modules or features work smoothly together as one system?
  • Could there be a better feature implementation? Like another framework, API, library, etc., to improve the solution.

Another important task in the feature review stage is the approval of all features by the stakeholders.

2. Non-functional requirements

Non-functional requirements refer to the overall quality and effectiveness of the software. NFRs have more to do with how the software works rather than what does it do? Some important non-functional requirements to consider during your code review are as follows:

Maintainability

Your software application should be easily supportable and maintainable in the future with minimum effort. It should be easy to detect and rectify a bug or an issue. Check for the following to ensure maintainable software:

a. Readability

The code should be self-explanatory with proper names for classes, functions, and variables. There should be no complexities, otherwise, it shows code needs refactoring. There should also be proper comments and documentation to understand a piece of code efficiently.

Ask the following questions to assess if your developers have written a “clean code”:

  • Does the code prioritize clarity and speaks for itself?
  • Does the code fit on a standard laptop or desktop screen size; there are no unnecessary whitespaces, etc.;
  • Is the proper naming convention (Pascal, CamelCase, etc.) been followed?
  • Could the readability be improved by breaking down the code into smaller methods;
  • Would method reconstruction improve the code flow?
  • Is the code in the right file or folder?
  • Is the data flow understandable?

b. Configurability

Your code should be configurable or customizable enough for changing data values without any extensive changes to the codebase. 

Your developers should have adhered to the following for writing a configurable application code:

  • Use of configuration files (JSON, XML, etc.) to store settings and parameters that are easily modifiable;
  • Storage of these configuration files outside the codebase for easy updates;
  • Use of environment variables to store configuration values based on deployment environments, like development, production, etc.;
  • Write functions with customizable parameters;
  • Use feature flags to enable or disable features without modifying the code.

c. Testability

Code testability would help you identify bugs early in the development cycle and ensure your code behaves as expected. Review your code testability by checking for the following:

  • The code is separated based on concerns, such as business logic, user interface, etc.;
  • Code is written in modules that can be tested separately;
  • There is a use of dependency injection, meaning there are no hard-coded dependencies, which allows you to replace the real dependencies with mock versions during testing;
  • There is a controlled use of global variables and states.

Reusability

Check your code for the DRY (Don’t Repeat Yourself) principle. There should be no repetitive code lines (code duplication). Ensure your developers have considered reusable services, functions, and components. Moreover, prioritize using generic classes and methods in your code.

Security

Code security is of utmost importance. You need to review the code for potential security vulnerabilities. No part of your code should introduce security threats. 

Ensure your developers adopt the best security practices while writing the application code. These include:

  • Authentication and authorization;
  • Input data validation against security threats, like SQL injections;
  • Sensitive data encryption;
  • Security of data received from external APIs or libraries, etc.;
  • Discontinue the use of any outdated tools or libraries.

Performance

Look for performance issues and also opportunities for performance improvement. Use profiling tools, like cProfile, Java VisualVM, GNUgprof, Visual Studio profiler, etc., to measure performance bottlenecks and optimize code for speed. 

Your code performance checklist should consider the following:

  • Use of suitable data types;
  • Use of efficient algorithms;
  • Application of lazy loading, caching, etc.;
  • No inefficient string concatenation, object allocations, etc.;
  • Database optimization;
  • Use of concurrency and parallel processing where applicable;
  • Optimization of resource-intensive operations.

3. Code design

You need to review the underlying code design and architecture of the application. Focus on the following:

Design Patterns

  • Are proper design patterns, like Builder, Singleton, Decorator, Command, etc., applied according to the design problem?

Single Responsibility Principle

  • Does every function or class have one responsibility?
  • Are classes and methods that perform too much avoided?

Open-Closed Principle

  • Does the code offer easy extensibility in case there is a need to modify the existing code?
  • Are extension points defined where needed in the code?

Interface Segregation Principle

  • Are interfaces designed to meet the requirements of specific software components?
  • Are unnecessary features avoided in the user interface?

Dependency Inversion Principle

  • Are high-level modules separated from low-level details via abstraction?
  • Is dependency injection correctly implemented?

Layered Architecture (if applicable)

  • Is the separation between application layers well-defined if the application follows a layered approach, such as mode-view-controller (MVC)?

4. Code formatting

You need to ensure proper formatting so that there is a consistent codebase that reduces potential coding errors and lays a stronger foundation for collaboration among your developers. Review the following:

Indentation

  • Is code properly indented using tabs or spaces?
  • Is the indentation consistent throughout the code?

Braces and Brackets

  • Are opening and closing braces/brackets placed properly and consistently?

Line Length

  • Are code lines of reasonable maximum length?
  • Are lines wrapped appropriately to ensure code readability?

Comment Formatting

  • Do comments include proper descriptions and follow proper indentation?
  • Does comment formatting follow the chosen coding style?

String Formatting

  • Are string literals formatted properly in single or double quotes?
  • Are multi-line strings formatted correctly?

Tools and Plugins

  • Are your developers using the relevant tools and plugins to ensure accurate and consistent formatting throughout the code base? Some examples include Prettier, Black, clang-format, Eclipse Code Formatter, etc.

Code Editor Settings

Mostly, development teams prefer defining a style guide for coding. You need to ensure:

  • Is the same coding style followed throughout the code base?
  • Are code editor settings configured correctly to support the desired formatting style?

5. Documentation

  • Well-maintained documentation would ensure better understanding and maintenance of the code while enforcing effective collaboration among the project team members. 
  • You need to review the following for the software code documentation:

Function and Method Documentation

  • Docstrings or in-line code documentation that explains functions and methods, including their usage, parameters, return values, examples, etc.

Class and Module Documentation

  • Explanation of classes and their intended purpose. Accurate definition of class attributes and methods.

API Documentation

  • A detailed explanation of APIs, including their parameters, endpoints, expected outputs, usage, etc.

Design and Architecture Decisions

  • Documentation that explains the selected code design and architecture and the reasons behind choosing them.

Change Log

  • A change log that documents significant code changes and bug fixes. This helps users and contributors stay informed of new changes to the code base.

Troubleshooting and FAQs

  • Troubleshooting guides and answers to frequently asked questions that help users properly run the application and resolve common issues.

Update and Maintenance Guidelines

  • Instructions to properly maintain and update the code, including version control practices.

Contributing Guideline

  • There should be proper guidelines for developers to contribute code, report bugs, submit pull requests, etc.

Ready to Conduct a Code Review?

Code review is a fundamental part of the software development process as it helps ensure the development of maintainable, readable, secure, and robust software applications. 

Moreover, it ensures better collaboration and knowledge sharing between developers and other project members. 

While a comprehensive code review checklist can help undertake the review process efficiently, code review is a critical and complex task. 

You need experienced developers with skills in developing feature-rich software applications to meticulously review the code base for functionality and issues.

Learn how to form a good code review strategy in our blog here

If you need expert developers to perform your code review or develop innovative software applications, DevTeam.Space can help you via a field-expert developers community. All our developers are motivated, skilled in cutting-edge technologies, and managed by senior developers. 

You can send us your initial project specifications via this quick form, and one of our account managers will contact you shortly for further assistance.

FAQs on a Code Review Checklist

1. What is a code review checklist?

A code review checklist is a set of guidelines and practices code reviewers follow while reviewing code written by their peer developers. Some software companies mistake code reviews as a process to guide junior team members to write good code or just a quality check. Code review refers to a systematic way to ensure adherence to coding guidelines and code quality standards and a code review checklist helps implement it effectively.

2. What are the steps to review code?

Code review aims to improve the quality of the overall software product and requires excellent skills. To perform effective code reviews, you need to go through the following steps:
Understand the context;
Pull the changes (pull request or code retrieval);
Perform code review by examining code changes, following the logic, identifying issues, etc.;
Comment on the code;
Discuss issues, and suggest changes to the code.
You can use automated code review tools to accelerate the code review process. Static code analysis tools also help to efficiently parse source code errors and security vulnerabilities.

3. Why is the code review checklist important?

A code review checklist ensures consistent coding standards and strengthens quality assurance. It helps to build a secure application, accelerate code deployment cycles, ensure requirement validation, etc. Moreover, code review checklists help with a thorough application review that fosters knowledge sharing among developers and enables continuous improvement of the code base via specific and actionable feedback from a code reviewer.


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